public class Cat {
    public static void main(String[] args) throws Exception {
        // 类是模板，对象是具体的
        Cat cat1 = new Cat();
        Cat cat2 = new Cat();
        Cat cat3 = new Cat();
        Class aClass1 = cat1.getClass();
         Class aClass2 = cat2.getClass();
         Class aClass3 = cat3.getClass();
         System.out.println(aClass1 == aClass2); // true
         System.out.println(aClass1 == aClass3); // true
         System.out.println(aClass2 == aClass3); // true
        
         String s = "hello world";
         System.out.println(s.getClass().getClassLoader());
         ClassLoader classLoader = aClass1.getClassLoader();
         System.out.println(classLoader); // AppClassLoader
         System.out.println(classLoader.getParent()); // ExtClassLoader
         System.out.println(classLoader.getParent().getParent()); // null BootstrapClassLoader
    }
}
